Embedded Files
Manufacturing Introduction
Manufacturing Introduction
Take a look at the CAD Model to the left. In order to manufacture The-Franny, it is important to split the device into sub-systems. Each of these color-coded subsystems have their own respective manufacturing processes. Let's investigate each of them step by step.
Framing (yellow)
Collapsing X-Frame (red)
Seat (pink)
Seat Latches (blue)
Stopper Pieces (orange)
X-Frame Connectors (green)
Traditional Manufacturing
Traditional Manufacturing
Uses techniques to remove material from stock. Processes include drilling, cutting, and sanding. Parts achieve the desired shape and configuration through welding and bending techniques.
Framing
Framing
The main framing of The-Franny is made of 6061 Aluminum Tubing that needs to be bent, notched, cut, and welded. The first step is to prepare a cutsheet that will provide the appropriate lengths of tubing that need to be bent.
Profile Sketch of Main Frame
To use the weldments feature in Solidworks, begin by creating a profile sketch of the frame. All dimensions listed above are in inches.
Note: At the Society of Automotive Engineers (SAE) mechanic shop, there is a 4.5" radius die that can be used to bend the tube. All bends shown above reflect this dimension. These bends will require more tubing length than the arc lengths shown in the below cutsheet.
Isometric View of Main Frame
Parts List (left) and Side Profile of Frame with Labeled Sections (right)
JD2 Model 3 Tube Bender
A 180 degree bend preformed on the bending machine to prepare the arm rest framing.
Tube Bent
A tube after bending. The line marked in red indicates the onset of bending which is directly measured with reference to the cutsheet.
Any interfaces that are to be welded need to be cut to length and notched using a Contour Machine and Saw Tube Notcher.
TIG (Tungsten Inert Gas) Welding 6061 Aluminum requires preparation. All areas that are notched must be filed and sanded down to remove any burrs and coatings while polishing the surface. Isopropyl alcohol is used in the end to remove any dust and finish the preparation.
TIG Welding and Post Polishing Demonstration Videos
IMG_9438.MOVvideo-1652761564.mp4Collapsing X-Frame
Collapsing X-Frame
The collapsing X-frame is the section that holds the two frame halves together and allows the walker to fold in when not in use. It is comprised of a steel inner piece and two 6061 Aluminum outer pieces. Manufacturing processes include drilling, pressing, welding, and belt sanding.
Drawing File of Outer Piece
Jet J-2530 15” Bench Model Drill Press
Used to drill the three holes that make up each set of outer pieces and inner piece. A 3/8" drill bit was used to make each hole.
Carver Laboratory Press
Used to press the outer pieces made of 6061 aluminum tubing into flat segments that will assemble with the rest of the components.
X-frame assembled together
Advanced Manufacturing
Advanced Manufacturing
Uses techniques such as Laser Cutting to achieve precise cutouts and drill holes. Reduces manufacturing and post-processing time and errors.
Seat
Seat
The seat, initially intended to be made with 1-inch thickness wood and CNC milled across each end, was made with 0.5" thickness MDF (Medium Density Fibreboard). A Nova 51 Laser Cutter was used to cut the outline and drill holes that would connect the seat to the 3D printed latch components.
Nova 51 Laser Cutter
Seat Component
The seat was cut at a power rating of 100 V and 15 mm/s. The operation was done several times to ensure a proper cut through the full depth of the board.
Additive Manufacturing
Additive Manufacturing
The use of a 3D Printer to produce custom components made with PLA filament. All parts are made with 80% in-fill density and tolerances are tested to press-fit fasteners.
Seat Latches
Seat Latches
The seat latches are the integral components that allow the seat to maintain two states of functionality: operation mode and rest mode. While The-Franny is in operation, the seat is folded up and clasped to the upper framework. When in rest mode, the latches rest on each side frame's lower bars so that the user can comfortably sit.
Latch 1A
Latch 1B
Latch 2A
Latch 2C-1
The latch components shown above join together using a Mortise and Tenon joint with appropriate tolerances. Latch 2C are joined to Latch 2A using a lap joint.
Stopper Pieces
Stopper Pieces
The stopper pieces are critical to the walker as they restrict the motion of the X-frame mechanism. Without them, The-Franny would extend its X-frame until it catches onto the lower bar of the frames. This could damage the 3D printed components, but more importantly, injure the user.
Stopper 1A - Top View
Stopper 1A - Alternative View
Stopper 1B - Top View
Stopper 1B - Alternative View
The stopper components shown above join together using a Tongue and Groove joint with appropriate tolerances. Additional cutouts and holes are made to integrate the 1/4" diameter screw and bolts.
X-Frame Connectors
X-Frame Connectors
The X-frame connectors integrate the X-frame subsystem with the framing. With the appropriate gaps to support the inner and outer pieces of the X-frame, the connectors allow a smooth transition from operation and folded mode.
Upper Piece A
Upper Piece B
Lower Piece A
Lower Piece B
The upper set of connector pieces are fixed to the framing. That is why additional cutouts and holes are made to integrate the 1/4" diameter screw and bolts. The lower set of connector pieces are free to move along the framing within the bounds of the installed stopper pieces.
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